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Fully magnetically levitated LV assist system shows positive outcomes in HF
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In the single-arm, prospective, multicenter HM3 CE Mark study, a full magnetically levitated left ventricular assist system showed favorable safety and efficacy outcomes in patients with advanced HF.
The HeartMate 3 LV assist system (St. Jude Medical) was designed to provide enhanced hemocompatibility and long-term support for patients with advanced HF. The system is placed within the pericardium with the inflow conduit inserted into the left ventricle and the outflow graft secured to the ascending aorta. The fully magnetically levitated rotor has large blood-flow paths (0.5 mm along the side and 1 mm above and below the rotor) to reduce shear forces. According to the researchers, this design may lessen adverse outcomes associated with other LV assist systems.
“This rotor design avoids the need for mechanical bearings, reducing wear of the moving component and heat generation within the pump,” Ivan Netuka, MD, PhD, of the Institute for Clinical and Experimental Medicine in Prague, and colleagues wrote. “The device’s internal surfaces are textured with titanium microspheres to promote adhesion of patient cells for reduced thrombogenicity.”
Researchers analyzed 50 adults (ejection fraction ≤ 25%, cardiac index ≤ 2.2 L/min/m2 without inotropes or were inotrope-dependent, on optimal medical management, or listed for transplant) at 10 centers in six countries to evaluate the performance and safety of the HeartMate 3.
Half of the patients had indications to use the LV assist system as a bridge to transplantation, whereas 46% had an indication for destination therapy.
The primary endpoint was 6-month survival compared with performance goals derived from INTERMACS.
At 6 months, 88% of patients continued on support, 4% received transplants and 8% died. The 6-month survival rate was 92%, which was higher than the 88% INTERMACS performance goal (HR = 0.34; P = .0093).
The HeartMate 3 reduced mortality risk by 66%, which was lower than the Seattle Heart Failure Model-predicted survival of 78% (P = .0093).
One of the four deaths recorded was due to postoperative ischemic stroke within the first 30 days. The other deaths, the researchers wrote, were not related to the device or procedure.
Adverse events during the 6-month period included bleeding (38%), infections (36%) and stroke (12%). The researchers did not report any pump exchanges, pump malfunctions, pump thrombosis or hemolysis events.
NYHA classification (P < .0001), 6-minute walk test (P < .0001) and quality-of-life scores (P < .0001) also showed improvement within the 6-month period.
Before the device was implanted, the mean cardiac index was 1.82 ± 0.46 L/min/m2. After implantation, the index increased to 2.2 ± 0.33 L/min/m2 (P < .0001). Average pump flow after implantation was 4.3 ± 0.6 L/min at 5,424 ± 309 rpm.
The researchers noted that “the adverse event types and rates are consistent with expected complications in the advanced HF population.”
“The first human experience with the new HeartMate 3 LV [assist system] has demonstrated that the pump performs as designed as is safe in an advanced population that included a mix of both [bridge to transplant] and permanent-support patients under a single set of study entry criteria,” Netuka and colleagues wrote.
The researchers concluded that more research is needed to determine whether there is a reduction of adverse events with this device. – by Tracey Romero
Disclosure: The study was sponsored by St. Jude Medical. Netuka reports consulting for and receiving grants from St. Jude Medical. Please see the full study for a list of all other authors’ relevant financial disclosures.
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